diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 3988a11df..5ab5704d8 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -76,7 +76,7 @@ jobs:
           gradle-version: 8.14
 
       - name: Build with Gradle and spring security ${{ matrix.spring-security }}
-        run: ./gradlew clean build
+        run: gradle clean build -x spotlessApply -x spotlessCheck
         env:
           DISABLE_ADDITIONAL_FEATURES: ${{ matrix.spring-security }}
 
@@ -161,7 +161,7 @@ jobs:
         uses: gradle/actions/setup-gradle@4d9f0ba0025fe599b4ebab900eb7f3a1d93ef4c2 # v5.0.0
 
       - name: Generate OpenAPI documentation
-        run: ./gradlew :stirling-pdf:generateOpenApiDocs
+        run: gradle :stirling-pdf:generateOpenApiDocs
         env:
           DISABLE_ADDITIONAL_FEATURES: true
 
@@ -191,7 +191,7 @@ jobs:
           distribution: "temurin"
 
       - name: Check licenses for compatibility
-        run: ./gradlew clean checkLicense
+        run: gradle clean checkLicense
         env:
           DISABLE_ADDITIONAL_FEATURES: false
           STIRLING_PDF_DESKTOP_UI: true
@@ -244,7 +244,7 @@ jobs:
 
       - name: Install Docker Compose
         run: |
-          sudo curl -SL "https://github.com/docker/compose/releases/download/v2.37.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
+          sudo curl -SL "https://github.com/docker/compose/releases/download/v2.40.3/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
           sudo chmod +x /usr/local/bin/docker-compose
 
       - name: Set up Python
@@ -296,17 +296,21 @@ jobs:
           gradle-version: 8.14
 
       - name: Build application
-        run: ./gradlew clean build
+        run: gradle clean build -x spotlessApply -x spotlessCheck
         env:
           DISABLE_ADDITIONAL_FEATURES: true
           STIRLING_PDF_DESKTOP_UI: false
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@c7c53464625b32c7a7e944ae62b3e17d2b600130 # v3.7.0
+        with:
+          platforms: linux/amd64,linux/arm64/v8
 
       - name: Set up Docker Buildx
         id: buildx
         uses: docker/setup-buildx-action@e468171a9de216ec08956ac3ada2f0791b6bd435 # v3.11.1
+        with:
+          platforms: linux/amd64,linux/arm64/v8
 
       - name: Convert repository owner to lowercase
         id: repoowner
@@ -335,6 +339,15 @@ jobs:
           provenance: false
           sbom: false
 
+      - name: Test Java works (amd64)
+        run: docker run --rm ${{ steps.meta.outputs.tags }} java -version
+
+      - name: Prune amd64 image and cache
+        if: always()
+        run: |
+          docker image rm -f ${{ steps.meta.outputs.tags }} || true
+          docker builder prune --force || true
+
       - name: Build and load arm64 image
         uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
         with:
@@ -350,9 +363,6 @@ jobs:
           provenance: false
           sbom: false
 
-      - name: Test Java works (amd64)
-        run: docker run --rm ${{ steps.meta.outputs.tags }} java -version
-
       - name: Test Java works (arm64)
         run: docker run --rm --platform linux/arm64 ${{ steps.meta.outputs.tags }} java -version
 
@@ -369,7 +379,7 @@ jobs:
 
           # LibreOffice binary linkage
           docker run --rm --platform linux/arm64 $TAG \
-            sh -c "ldd /usr/bin/soffice.bin > /dev/null && echo 'LibreOffice binary linked OK'" || \
+            sh -c "ldd /usr/lib/libreoffice/program/soffice.bin > /dev/null && echo 'LibreOffice binary linked OK'" || \
             (echo "LibreOffice binary broken on arm64!" && exit 1)
 
           # Python uno import
@@ -378,12 +388,31 @@ jobs:
             (echo "Python uno import failed on arm64!" && exit 1)
 
           # Full startup
-          timeout 180 docker run --rm --platform linux/arm64 \
-            -e DISABLE_ADDITIONAL_FEATURES=true \
-            -e FAT_DOCKER=true \
+          TAG="${{ steps.meta.outputs.tags }}"
+          echo "Running quick startup check on arm64..."
+
+          docker run --rm --platform linux/arm64 \
             $TAG \
-            sh -c "java -jar /app.jar --version && echo 'Stirling-PDF fat started on arm64!'" || \
-            (echo "Startup failed on arm64!" && exit 1)
+            sh -c "java -jar /app.jar --version || java -jar /app.jar --help || java -jar /app.jar" > startup.log 2>&1 &
+
+          # Warte max. 90 Sekunden und prüfe, ob die Startzeile mit Version erscheint
+          timeout 90 bash -c "
+            until grep -q 'Starting SPDFApplication v' startup.log; do
+              sleep 2
+              if ! kill -0 \$! 2>/dev/null; then
+                echo 'Java process died!'
+                cat startup.log
+                exit 1
+              fi
+            done
+            echo 'Stirling-PDF fat started successfully on arm64!'
+          " || (echo "Startup failed:"; cat startup.log; exit 1)
+
+      - name: Cleanup arm64 image and cache
+        if: always()
+        run: |
+          docker image rm -f ${{ steps.meta.outputs.tags }} || true
+          docker builder prune --force || true
 
       - name: Upload Docker build reports
         if: always()
diff --git a/Dockerfile.fat b/Dockerfile.fat
index fa4271d36..5ade20ddc 100644
--- a/Dockerfile.fat
+++ b/Dockerfile.fat
@@ -17,15 +17,68 @@ WORKDIR /app
 COPY . .
 
 # Build the application with DISABLE_ADDITIONAL_FEATURES=false
-ENV DISABLE_ADDITIONAL_FEATURES=false \
-    STIRLING_PDF_DESKTOP_UI=false
+ENV DISABLE_ADDITIONAL_FEATURES=false STIRLING_PDF_DESKTOP_UI=false
 RUN ./gradlew clean build -x spotlessApply -x spotlessCheck -x test -x sonarqube
 
 # Main stage
-FROM alpine:3.22.2@sha256:4b7ce07002c69e8f3d704a9c5d6fd3053be500b7f1c69fc0d80990c2ad8dd412
+FROM alpine:3.20
 
-ARG LIBREOFFICE_VERSION=25.2.6
-ARG TARGETARCH=amd64
+ARG VERSION_TAG
+
+# Community-Repo aktivieren
+RUN echo "http://dl-cdn.alpinelinux.org/alpine/v3.20/community" >> /etc/apk/repositories
+
+# Alle Pakete in einem RUN
+RUN --mount=type=cache,target=/var/cache/apk \
+    apk upgrade --no-cache && \
+    apk add --no-cache \
+    ca-certificates \
+    tzdata \
+    tini \
+    bash \
+    curl \
+    shadow \
+    su-exec \
+    openssl \
+    openssl-dev \
+    openjdk21-jre \
+    ffmpeg \
+    # Doc conversion
+    gcompat \
+    libc6-compat \
+    libreoffice \
+    poppler-utils \
+    tesseract-ocr \
+    tesseract-ocr-data-eng \
+    tesseract-ocr-data-chi_sim \
+    tesseract-ocr-data-deu \
+    tesseract-ocr-data-fra \
+    tesseract-ocr-data-por \
+    unpaper \
+    font-terminus \
+    font-dejavu \
+    font-noto \
+    font-noto-cjk \
+    font-awesome \
+    font-noto-extra \
+    font-liberation \
+    font-linux-libertine \
+    font-urw-base35 \
+    python3 \
+    py3-pip \
+    py3-opencv \
+    ocrmypdf \
+    py3-pillow \
+    py3-pdf2image
+
+# Python venv + pip packages
+RUN set -eux; \
+    python3 -m venv /opt/venv && \
+    /opt/venv/bin/pip install --no-cache-dir --upgrade pip setuptools && \
+    /opt/venv/bin/pip install --no-cache-dir --upgrade unoserver weasyprint && \
+    ln -s /usr/lib/libreoffice/program/uno.py /opt/venv/lib/python3.12/site-packages/ && \
+    ln -s /usr/lib/libreoffice/program/unohelper.py /opt/venv/lib/python3.12/site-packages/ && \
+    ln -s /usr/lib/libreoffice/program /opt/venv/lib/python3.12/site-packages/LibreOffice
 
 # Copy necessary files
 COPY scripts /scripts
@@ -33,7 +86,18 @@ COPY app/core/src/main/resources/static/fonts/*.ttf /usr/share/fonts/opentype/no
 # first /app directory is for the build stage, second is for the final image
 COPY --from=build /app/app/core/build/libs/*.jar app.jar
 
-ARG VERSION_TAG
+
+# Verzeichnisse, Fonts, Rechte
+RUN set -eux; \
+    mv /usr/share/tessdata /usr/share/tessdata-original && \
+    mkdir -p /home/stirlingpdfuser /configs /logs /customFiles /pipeline/watchedFolders /pipeline/finishedFolders /tmp/stirling-pdf && \
+    ln -s /usr/share/fontconfig/conf.avail/69-urw-*.conf /etc/fonts/conf.d/ && \
+    fc-cache -f -v && \
+    chmod +x /scripts/* && \
+    addgroup -S stirlingpdfgroup && adduser -S stirlingpdfuser -G stirlingpdfgroup && \
+    chown -R stirlingpdfuser:stirlingpdfgroup \
+    /home/stirlingpdfuser /scripts /usr/share/fonts/opentype/noto \
+    /configs /customFiles /pipeline /tmp/stirling-pdf /app.jar
 
 # Set Environment Variables
 ENV DISABLE_ADDITIONAL_FEATURES=true \
@@ -46,135 +110,15 @@ ENV DISABLE_ADDITIONAL_FEATURES=true \
     UMASK=022 \
     FAT_DOCKER=true \
     INSTALL_BOOK_AND_ADVANCED_HTML_OPS=false \
-    PYTHONPATH=/opt/libreoffice/program:/opt/venv/lib/python3.12/site-packages \
-    UNO_PATH=/opt/libreoffice/program \
-    URE_BOOTSTRAP=file:///opt/libreoffice/program/fundamentalrc \
+    PYTHONPATH=/usr/lib/libreoffice/program:/opt/venv/lib/python3.12/site-packages \
+    UNO_PATH=/usr/lib/libreoffice/program \
+    URE_BOOTSTRAP=file:///usr/lib/libreoffice/program/fundamentalrc \
     PATH=$PATH:/opt/venv/bin \
     STIRLING_TEMPFILES_DIRECTORY=/tmp/stirling-pdf \
     TMPDIR=/tmp/stirling-pdf \
     TEMP=/tmp/stirling-pdf \
     TMP=/tmp/stirling-pdf
 
-# JDK for app
-RUN printf '%s\n' \
-      'https://dl-3.alpinelinux.org/alpine/edge/main' \
-      'https://dl-3.alpinelinux.org/alpine/edge/community' \
-      'https://dl-3.alpinelinux.org/alpine/edge/testing' \
-      > /etc/apk/repositories
-
-# Bash + repositories
-RUN apk add --no-cache bash && \
-    ln -sf /bin/bash /bin/sh
-
-RUN --mount=type=cache,target=/var/cache/apk \
-    apk upgrade --no-cache -a
-
-RUN --mount=type=cache,target=/var/cache/apk \
-    apk add --no-cache \
-    ca-certificates \
-    tzdata \
-    tini \
-    bash \
-    curl \
-    shadow \
-    su-exec \
-    openssl \
-    openssl-dev \
-    openjdk21-jre \
-    dpkg
-
-RUN --mount=type=cache,target=/var/cache/apk \
-    apk add --no-cache \
-    ffmpeg \
-    # Doc conversion
-    gcompat \
-    libc6-compat \
-    unpaper \
-    poppler-utils \
-    icu-libs \
-    icu-dev \
-    libstdc++
-
-# RUN --mount=type=cache,target=/var/cache/apk \
-#     apk add --no-cache \
-#     libreoffice
-
-RUN --mount=type=cache,target=/var/cache/apk \
-    apk add --no-cache \
-    # OCR MY PDF (unpaper for descew and other advanced featues)
-    tesseract-ocr-data-eng \
-    tesseract-ocr-data-chi_sim \
-    tesseract-ocr-data-deu \
-    tesseract-ocr-data-fra \
-    tesseract-ocr-data-por
-
-RUN --mount=type=cache,target=/var/cache/apk \
-    apk add --no-cache \
-    unpaper \
-    font-terminus font-dejavu font-noto font-noto-cjk font-awesome font-noto-extra font-liberation font-linux-libertine font-urw-base35 \
-    # CV / Python
-    py3-opencv \
-    python3 \
-    ocrmypdf \
-    py3-pip \
-    py3-pillow \
-    py3-pdf2image
-
-RUN --mount=type=cache,target=/var/cache/apk \
-    # Calibre (musl-native) + QtWebEngine Runtime
-    apk add --no-cache calibre && \
-    # Calibre fixes
-    apk fix --no-cache calibre
-
-RUN set -eux; \
-    case "${TARGETARCH}" in \
-        amd64) libreoffice_arch="x86-64" ;; \
-        arm64) libreoffice_arch="aarch64" ;; \
-        *) echo "Unsupported TARGETARCH: ${TARGETARCH}" >&2; exit 1 ;; \
-    esac && \
-    curl -fsSL "https://download.documentfoundation.org/libreoffice/stable/${LIBREOFFICE_VERSION}/deb/${libreoffice_arch}/LibreOffice_${LIBREOFFICE_VERSION}_Linux_${libreoffice_arch}_deb.tar.gz" -o /tmp/lo.tar.gz
-
-RUN set -eux; \
-    mkdir -p /tmp/libreoffice && \
-    tar -xzf /tmp/lo.tar.gz -C /tmp/libreoffice --strip-components=1 && \
-    for pkg in /tmp/libreoffice/DEBS/*.deb; do \
-        dpkg-deb -x "${pkg}" /; \
-    done && \
-    libreoffice_dir="$(find /opt -maxdepth 1 -type d -name 'libreoffice*' | head -n 1)" && \
-    [ -n "${libreoffice_dir}" ] && \
-    rm -f /opt/libreoffice && \
-    ln -sf "${libreoffice_dir}" /opt/libreoffice && \
-    rm -f /usr/bin/soffice /usr/bin/soffice.bin && \
-    ln -sf /opt/libreoffice/program/soffice /usr/bin/soffice && \
-    ln -sf /opt/libreoffice/program/soffice.bin /usr/bin/soffice.bin && \
-    rm -rf /tmp/libreoffice /tmp/lo.tar.gz
-
-RUN python3 -m venv /opt/venv && \
-    /opt/venv/bin/pip install --no-cache-dir --upgrade pip setuptools && \
-    /opt/venv/bin/pip install --no-cache-dir --upgrade unoserver weasyprint && \
-    ln -s /opt/libreoffice/program/uno.py /opt/venv/lib/python3.12/site-packages/ && \
-    ln -s /opt/libreoffice/program/unohelper.py /opt/venv/lib/python3.12/site-packages/ && \
-    ln -s /opt/libreoffice/program /opt/venv/lib/python3.12/site-packages/LibreOffice && \
-    mv /usr/share/tessdata /usr/share/tessdata-original && \
-    mkdir -p $HOME /configs /logs /customFiles /pipeline/watchedFolders /pipeline/finishedFolders /tmp/stirling-pdf && \
-    # Configure URW Base 35 fonts
-    ln -s /usr/share/fontconfig/conf.avail/69-urw-*.conf /etc/fonts/conf.d/ && \
-    fc-cache -f -v && \
-    chmod +x /scripts/* && \
-    # User permissions
-    addgroup -S stirlingpdfgroup && adduser -S stirlingpdfuser -G stirlingpdfgroup && \
-    chown -R stirlingpdfuser:stirlingpdfgroup \
-        $HOME \
-        /scripts \
-        /usr/share/fonts/opentype/noto \
-        /configs \
-        /customFiles \
-        /pipeline \
-        /tmp/stirling-pdf \
-        /app.jar && \
-    # chmod 755 /usr/bin/soffice.bin && \
-    ln -sf /bin/busybox /bin/sh
-
 EXPOSE 8080/tcp
 # Set user and run command
 ENTRYPOINT ["tini", "--", "/scripts/init.sh"]